Recently I've found some time to swap the unimodal burrs for H-U for further testing, so measured also total retention after ca. 6 months of use.

Yeah, it remains fairly pristine.

Once the H-U burrs were mounted, I turned the lower carrier by hand while turning also the dialing collar simultaneously to check, where new zero point moved. I clearly felt burrs misalignment (thought about a huge one), touching each other only at some point (i.e. both burrs are misaligned, not only one of them). So I took Mitutoyo dial indicator and measured lower burr misalignment to know where it is and how much it is ... and found (only) 20, maybe max 30 um, hard to say!
Using a marker method and few attempts I placed finaly 1 layer + 3 layers + 1 layer of alu foil on the carrier at specific points.

Bottom burr before alignment


Lower carrier with alignment alu foils


Bottom burr after alignment



Top burr aligning was a piece of cake, requiring just 2x 1 layer of alu foil and only 1 attempt.

Top burr before alignment


Upper carrier with alignment foils


Top burr after alignment


New zero point of H-U burrs moved by 0.4 - 0.5 marks on my scale from original ZP (unimodal burrs), i.e. by only 0.02 - 0.025 mm in burrs gap change (1.0 mark = 0.05mm, 10 marks = 1 full collar turn).
Espresso setting changes from 1.5 - 1.8 marks (from ZP) for unimodal burrs to ca. 5.5 - 6.0 marks for H-U burrs (note: tested/coffee made before H-U alignment, so we'll see later ...).

Resume:
- Despite of at first glance "huge" misalignment feeling by hand real measurement turned into almost perfectly aligned stock grinder (I consider misalignment up to 50 um as OK);
- I also found out, that's very important do not overtight the screws too much - when the screws were tightened a bit more, I noticed the marker has been removed between the screws, but not near them - marker method alignment is that sensitive. I tried to use a torque wrench, but 4Nm torque (the lowest setting of my tool) is already too high;
- Personal finding: Due to extremely small misalignment deviations (speaking about 0.01mm values) checking the burrs misalignment simply by pushing on the collar from the side to hear if there is a rub or not is technically a nonsense.

What I did when I aligned both my EK and Mazzer recently was trying out all three possible mounting options for every burrs, measuring the result with a feeler gauge between the burrs through the opening from the chamber to the doser, rotating the burr by hand from the top and felt where the burrs locked on the gauge vs. where it had openings and marked the spots with the most gap with a marker on the side of the burrs. With the EK I also used a dial indicator on the static burr to check which position was the most optimal.

That got me very close to the best alignment before I ended up putting one layer of alu foil at a single spot in the Mazzer (nothing in the EK) and that made the alignment about as good as without the foil so the misalignment of the burr is like half a layer of foil. With the Mazzer and I assume the Lagom, I also checked all three ways to mount the static burr holder in the grinder, so there is 9 different combinations of burr error and burr holder mounted in grinder error to get the best starting point before shimming. Mark everything and install everything the same every time to keep you from chasing your own tail.

Quick version is to check all mounting options and see where the zero point moves the finest position on the dial and sound of burrs rubbing is the most on/off over the shortest travel of the dial. You can close the burrs so that you lock the burrs together without the motor running (don't crank too hard, use the same force each time and do it multiple times every time to feel confident about it) mark that reference spot, move dial coarser, run grinder, and then see where the first sound from burr rub is on the indicator, how many indicator markings it's off from burr lock.

Peter_SVK wrote:So I took Mitutoyo dial indicator and measured lower burr misalignment to know where it is and how much it is ... and found (only) 20, maybe max 30 um, hard to say!
Using a marker method and few attempts I placed finaly 1 layer + 3 layers + 1 layer of alu foil on the carrier at specific points.

Did you check it by using the dial indicator again after shimming? My ditting 804 Lab Sweet also has 20 microns misalignment on the lower burr, checked by Mitutoyo dial indicator. I reduced it to under 5 microns by shimming. But I finally removed the aluminum foils after 2 years use and prefer the taste of non-shimming for pour over. For espresso, I did not find big difference.

Peter_SVK wrote:Personal finding: Due to extremely small misalignment deviations (speaking about 0.01mm values) checking the burrs misalignment simply by pushing on the collar from the side to hear if there is a rub or not is technically a nonsense.

Just curious, after completing shimming, did you use the marker test again to check the effect of side pushing the collar to see how many markers removed by the tilting upper burr? My Lagom zero point could be moved up to 0.1 when I dialed it back and forth before modifying it, which meant I pushed the collar from the side unconsciously when I dialed it and tilted the upper burr up to 10 microns. I have no idea how much the 10 microns effect was. After modifying it, I have no such issue now.

Shimming took me 4 hours and finished it in the late night, so I was happy when it has been done yet. I didn't check again with dial indicator after shimming because marker trace looks OK for me (you know for sure that measuring with dial indicator is not a fast process at all ).

No I didn't (... was happy finished the shimming ... ), and there is not good technical explanation what does that test means for actual burrs alignment.

Latest news:
Making espresso today morning I noticed there is no shift/move of grinder setting for extraction after shimming (compared to the grinder setting before shimming). This also confirms my view that 20 or 30 (or even 50) microns (in mm: 0.02 - 0.03, 0.05) of burrs misalignment is negligible and perfectly tolerable.

Peter_SVK wrote:Shimming took me 4 hours and finished it in the late night, so I was happy when it has been done yet. I didn't check again with dial indicator after shimming because marker trace looks OK for me (you know for sure that measuring with dial indicator is not a fast process at all ).

Exactly. I took 4 hours for my 804 Lab Sweet as well.

Peter_SVK wrote:Recently I've found some time to swap the unimodal burrs for H-U for further testing

I am looking forward hearing about your opinion on the HU burrs. I was not overly impressed (after aligning and seasoning)...clarity was there but the taste felt somewhat monochromatic, and sweetness was relatively low... Peter, you previously mentionned that you set the speed of your grinder to 6. Do you prefer this over Option-O recommendation, which is 7 for espresso?

On the other hand I am very positively surprised by the Option-O custom version of the Unimodal burrs (I guess they are now actually bi-modal since there is a flat surface to produce some fines). I just switched (and aligned the burrs and seasoned with 3 Kg of dark beans straight away) about two weeks ago. There is much more sweetness, clarity is there but altogether warm and rich, body surprisinlgy quite silky. At ratios of 1/2 and higher, I really prefer the new unimodal over the HU, for light, medium and med-dark as well. It is a first impression but I felt that the change was quite big. There are also two big pros: the ground produced are much less prone to channeling and the burrs do not make that whining sound when adjusting grind setting. So far I am very happy!

Based on the number of shims I had to use, the misalignement on mine was above 50 microns... seems like mine came I little off. Anyway this is now fixed and in my case, after aligning with the marker test, I needed to adjust the grind setting 3 small increments (latest version) coarser to get the same shot time.

I've swapped the burrs because already got it with the grinder, to make some change and to test the alignment. Frankly, if there is no option for blind testing side-by-side from unimodal and H-U burrs, the opinion is highly biased. It's hard to judge just from memory and on different beans. When I still had E65S (the same or at least similar burrs geometry like SSP H-U, which are told to be a copy of K30), me and my wife (she blindly) preffered the taste of Lagom unimodal burrs over E65S 13 : 1 of the tested samples. It looks to me like unimodal burrs produce a bit less acidity and bitterness compared to E65S (H-U) for lighter roasted beans (I do not drink darks or medium-darks).
Either you use 6 or 7 speed, I doubt there is any notable difference, even with TDS analyser. Maybe between 6 and 12 speed I've noticed subtle diffence for some beans if wanted to get some more fines to force a bitterness a bit and a bit supress the acidity, but this is just a speculation.

Some new fresh olive wood bling for Lagom ...